U.S. Pat. No. 5,584,644, granted Dec. 17, 1996, to David Droegemueller, and entitled, "Coupling System", discloses a prior art coupler for connecting an attachment to the free end of a boom or working arm on a backhoe, etc. This patent also describes the prior art that preceded the invention disclosed by the patent. The invention disclosed by the patent require two lock pins 30 and the assertion of these lock pins 30 through aligned openings in members 21, 28, 32 on a first side of the attachment and in members 22, 28, 32 on the opposite side of the attachment. A first hook structure 24 is positioned to engage a first coupler pin 17 on the attachment. A second hook structure 26 is positioned to receive a second coupler pin 18 on the attachment 12. Then, the hook structure 26 is swung upwardly to move the members 28 upwardly through openings 11A, and place the pin receiving openings into axial alignment on both sides of the attachment. Then, the lock pins 30 are inserted through the aligned openings to lock the hook structure 26 to the sidewalls 21, 22 of the coupler 10.
There is a need for an easier-to-use coupler that allows a quick and automatic coupling of the attachment to the coupler without anyone having to insert lock pins through aligned openings. A principal object of the invention is to provide such an improved coupler.
The aforementioned U.S. Pat. No. 5,584,644 and the prior art described in it should be carefully studied for the purpose of putting the present invention into proper prospective with respect to the prior art.